Isolation and characterization of bacteriophage SA14 with potential lytic and anti-biofilm activity against clinical multidrug-resistant Enterococcus faecalis

Research Abstract

Failure of antibiotics to combat drug-resistant organisms is a major contributing factor to the rise of multidrug-resistant bacteria. As a result, alternative treatments are more important than ever. In the present study, a multi-drug resistant E. faecalis was isolated from urine sample. VITEK®2 system and 16S rRNA gene sequencing and alignment were employed for identification, biochemical characterization and antibiotic susceptibility testing of the clinical isolate. The isolate showed a multi-drug resistant pattern to 8 antibiotics including vancomycin, streptomycin (high level synergy) and gentamicin (high level synergy) among others. Therefore, bacteriophage therapy was sought as an alternative to traditional antibiotics. Bacteriophage SA14; a member of Siphoviridae family as revealed by Transmission Electron Microscopy, was isolated from sewage water and further purified. The phage showed a characteristic stability to a wide range of pH and temperature with optimal at pH 7.4 and 37°C, however, was highly specific towards its host. Based on one-step growth curve data, the phage's latent period was 25 minutes, and the burst size was 20 PFU/ml. The lytic activity of phage SA14 was evaluated at various multiplicities of infection (MOI), all considerably suppressed the growth of the host organism. Moreover, phage SA14 displayed a characteristic antibiofilm activity as revealed by reduction in -adhered biomass and -viable cells of the pre-formed biofilm by 19.1-fold and 2.5-fold, respectively, at MOI of 100. Therefore, bacteriophage SA14 could be a viable option for the control of the multidrug-resistant E. faecalis and its associated biofilm.

Research Keywords

Enterococci, Bacteriophage, Vancomycin-resistance Enterococcus faecalis, in vivo wound mice model, Genome anal